Queen's Gambit Declined: Neo-Orthodox Variation

The Queen's Gambit Declined: Neo-Orthodox Variation is a chess opening classified under ECO code D54 in the Closed & Semi-Closed Games family, arising from 1.d4 d5, including the Queen's Gambit, Slav Defense, and related systems. It is reached after 6 moves: 1. d4 Nf6 2. c4 e6 3. Nc3 d5 4. Bg5 Be7 5. e3 O-O 6. Rc1. The resulting position leaves black to move.